Update Clang for 3.5 rebase (r209713).

Change-Id: I8c9133b0f8f776dc915f270b60f94962e771bc83
diff --git a/docs/CMakeLists.txt b/docs/CMakeLists.txt
index 635ea1f..20a1396 100644
--- a/docs/CMakeLists.txt
+++ b/docs/CMakeLists.txt
@@ -80,3 +80,12 @@
   endif()
 endif()
 endif()
+
+if (LLVM_ENABLE_SPHINX)
+  if (SPHINX_FOUND)
+    include(AddSphinxTarget)
+    if (${SPHINX_OUTPUT_HTML})
+      add_sphinx_target(html clang)
+    endif()
+  endif()
+endif()